Scatter PES

3-body classical scattering code on a quantum PES.

Please clone the repo:

git clone git@github.com:TomMelt/ScatterPES.git

Installation

To install on local machine:

pip install -U -e .

Core Dependencies

These package must be installed for scatter to run properly.

• numpy
• scipy
• xarray

Plotting Dependencies

Only required for the plotting functions.

• matplotlib

To Do

• Take a look at the classical action (zeroth order phase)
  • if it varies slowly it indicates classical nature
  • if it varies rapidly calculate the phase and interferance for quantum number n
  • classical action of whole system or of pbar?
• still need to write tests for:
  • classify.py
  • initialize.py
  • propagation.py
• Check how starting position affects the scattering velocities/ distro of nq
  • Could calculate the integral of energy gained by moving through 1/r pot.

Notes

• initially program was also built in spherical coords
  • this does not work well with RK4 prop because angles can be arbitrarily large and;
  • there are singularities in the equations of motion (1/sin^2(phi)) etc.
• Error in the Hamiltonian appears to come from close encounter of all three particles
  • tried using just short range potential < 5 a.u. but this was not successful
• E.E.Nikitin Jost W. (Ed.), Phys. chem., 6a, Academic Press, New York (1974) ch. 4
  • "one of the necessary conditions for the proper description in terms of a classical traj. is that changes in the De Broglie wavelength of the appropriate vars. be small over the scale determined by the spatial variation of the wavefunction"
  • "epsilonbb = l_c^2/2Mu"